We have millions of them in Italy, same problems as the British guys with lights, etc.
While I admit it does cut down on the left turn in front of you T bone accidents,
I'm still not sure I like them.
I am also worried about getting hit from behind, depending on traffic I usually do this:
With no traffic in my lane in front of me....
Slow down before.. hoping the car behind sees the brake light.
Most people will enter the roundabout with the attitude;
"I will slow down until I'm sure it's safe to go."
I adopt the attitude "I will go until I'm sure I have to stop."
With cars in front of me.....
Wait for them to clear, but leave 1-2 car spaces in front of me, then gun it thru the roundabout, leaving the car behind me 10-15 feet to move first before catching up.
The trick is make sure you occupy the space around you, and force the cagers
to.. 'acknowledge your presence.'